论文部分内容阅读
研究2024铝合金搅拌摩擦焊缝在空气、预腐蚀与3.5%盐水腐蚀液中的疲劳与裂纹扩展性能,并采用SEM对断口的近门槛区、稳定扩展区与瞬断区进行观测。结果表明,腐蚀环境对铝合金搅拌摩擦焊缝的寿命产生很大影响,焊缝的腐蚀疲劳寿命只有空气中的一半左右;焊缝的裂纹扩展速率比母材快,在腐蚀环境下,随着应力强度因子幅度的增大,母材与焊缝裂纹扩展速率的差距越来越大,但预腐蚀损伤对焊缝的裂纹扩展速率影响较小,只是降低了裂纹萌生寿命。
The fatigue and crack propagation properties of 2024 aluminum alloy friction stir welded seams in air, pre-corrosion and 3.5% saline solution were studied. SEM was used to observe the near-sill area, stable extension area and instantaneous fracture area of the fracture. The results show that the corrosion environment greatly affects the service life of aluminum alloy friction stir welding. The corrosion fatigue life of the weld is only about half of that in the air. The weld crack propagation rate is faster than that of the base metal. Under the corrosive environment, The difference of crack growth rate between base metal and weld increases with the increase of stress intensity factor, but the pre-corrosion damage has little effect on the crack propagation rate, but only reduces the crack initiation life.